Pneumatic pickoff for two degree of freedom gyro



May 23, 1967 J. v. JOHNSTON 3,320,816

PNEUMATIC PICKOFF FOR TWO DEGREE OF FREEDOM GYRO Filed Feb. 5, 1965James V. Johnston,

INVENTOR.

BY M J W W T. ikuL-a ATTORNEY United States Patent 3,320,816 PNEUMATICPICKOFF FOR TWO DEGREE (9F FREEDOM GYRO James V. Johnston, Huntsville,Ala., assignor to the United States of America as represented by theSecretary of the Army Filed Feb. 3, 1965, Ser. No. 430,223 8 Claims.(Cl. 74-5.6)

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment of anyroyalty thereon.

The invention relates to a two degree of freedom gyro with an allpneumatic system.

With the advent of fluid amplifiers and reaction control for missiles,an all pneumatic system is necessary including the inertial sensingdevice.

Therefore, it is an object of this invention to provide an all pneumaticsystem for a gyro.

Another object of this invention is to provide a gyro that allows forhigh g acceleration.

Still another object of this invention is to provide an extremely simplepneumatic gyro.

Yet another object of this invention is to provide a pneumatic gyro thatcan be fabricated from cheap component parts.

In accordance with this invention, a new pneumatic gyro system isprovided that includes a stationary spherical stator member about whicha rotor member is rotatably mounted by means including air bearingmeans. The rotor member has a reaction ramp surface against which fluid,from different positions around the stator member, is directed togenerate signals. Said signals are then utilized to control fluidamplifier means, and the outputs from the fluid amplifier means can beused to control devices desired in one or two degrees of freedom such ascontrol surfaces of a missile.

In the accompanying drawing forming a part of this specification, and inwhich like numerals are employed to designate corresponding partsthroughout the same:

FIGURE 1 is a view, partially in section, of a gyro in accordance withthis invention and illustrating the fluid amplifier means schematically,

FIGURE 2 is a sectional view taken on line 22 of FIGURE 1, and

FIGURE 3 is a view, partially in section, and taken on line 33 of FIGURE1.

The invention may be better understood by referring to the drawingwherein, numeral 1 designates a casing that supports stator member 3 bybeing secured thereto in a conventional manner. Stator member 3 has aspherical ball portion 5 about which a free rotor member 7 surrounds thestator in an equatorial plane. Spherical ball portion 5 and rotor member7 are separated by an air gap 9. Rotor member 7 is supported through theuse of air from a high pressure source 11 that is communicated throughpassage 12 to channels 13 in stator member 3 and into air gap 9.Exhausting of this air into air gap 9 creates pressure which floatsrotor member 7. Channels 13 open into the air gap so as to surround thespherical ball portion 5 and create a latitude band of support holds oneach end.

Rotor member 7 may be rotated by conventional means such as by turbinemeans of the type disclosed in U.S. Patent No. 2,086,896.

A pneumatic pickofl control for the gyro includes four control positionsor orifices 15, 17, 19, 21 (see FIG- URE 2), located 90 apart around theperiphery of spherical portion 5. Air or other gas is delivered from ahigh pressure supply means 23 to a manifold 25 and to each of the fourcontrol positions by way of fluid passages 27. Each fluid passage 27 hasan orifice or throttle 29 near manifold 25 and an orifice or throttle 31near the control position to define a chamber 33 between orifices 29 and31. Each chamber 33 communicates with a pickoff control passage 35 thathas an orifice 37 mounted therein. Pickoff control passages 35, forcontrol positions 15 and 19, are connected as opposing controls for afirst conventional type fluid amplifier 39, such as the push-pull type.Pickoff control passages 35 for control positions 17 and 21 areconnected as opposing controls for a second conventional type fluidamplifier 41. The outputs 40 and 42 from amplifiers 39 and 41 can beused to actuate control means as desired to control in one or twodegrees of freedom.

The control fluid supplied to control positions 15, 17, 19, 21 isdirected toward an inner circumferentially tapered ramp surface 43 onrotor 7 and exhausted through slots 45 in rotor 7 and exhaust opening 47in casing 1 (see FIG. 1).

In operation, air from source 11 is supplied to air gap 9 to supportrotor 7, and rotor 7 is rotated in a conventional manner by fluidturbine means. With the rotor rotating, air pressure from high pressuresupply means 23 is utilized to provide an air pressure p in manifold 25.Air is then communicated from manifold 25 to chambers 33 across orifices29 to establish p pressures in chambers 33. Air is next communicatedfrom chambers 33 across orifices 31 to control positions 15, 17, 19, 21.So long as the distances between the control positions and tapered rampsurface 43 remain equal, the p pressures in chambers 33 will be equal.However, for example, if rotor member 7 is pivoted to the right asviewed at the top of FIGURE 1, the distance between control position 15and the portion of tapered ramp surface 43 immediately above controlposition 51 will be greater than the distance between control position19 and the portion of tapered ramp surface 43 immediately below controlposition 19 to thereby cause the p pressure in chamber 33 for controlposition 19 to be greater than the p pressure for control position 15 byan amount proportional to the change in distance. That is, as the ppressure for control position 19 increases, the p pressure for controlposition 15 will decrease. The change in the p pressures will cause theflow rates through pickoff control passages 35 to change in proportionto the deviation of rotor 7 from an original rotor axis position andadapt the signals from control passages 35 to be used as opposingcontrols for controlling fluid amplifiers 39 and 41.

Also in operation, the p; pressure is chosen so as to be generally 10 to20 times higher than the p pressure, which makes the orifices orthrottles 29 very effective for not causing any variations in pressure por variations of flows through the orifices that might affect the ppressure.

This particular pneumatic design offers a completely coerciveless pickupand allows for the first time a true flow sensor to pneumaticamplifiers. Pneumatic amplifiers have always required flow rates ratherthan pressure, and with this concept and design, large flow rates can beachieved by simple manipuation of the orifices or throttles.

It is to be understood that the form of my invention, herewith shown anddescribed, is to be taken as a preferred example only, and that variouschanges in the size, shape and arrangement of parts may be resorted to,without departing from the spirit of my invention or the scope of thesubjoined claims.

I claim:

1. A two degree of freedom pneumatic gyro including: a rotor member; astator member; air bearing means between mating surfaces of said rotorand stator members and supporting said rotor member for rotationrelative to said stator member; and pneumatic pickofi control meansdisposed relative to said rotor and stator members and connected tofluid amplifier means for control thereof, said pneumatic pickoifcontrol means including means in said stator member mating surface andcoacting with means on said rotor member mating surface to establishflow rates to said fluid amplifier means that are proportional to themovement of said rotor member from a predetermined position, and meansin said rotor member for exhausting fluid from said means on said statormember mating surface.

2. A two degree of freedom pneumatic gyro as set forth in claim 1,wherein said rotor and stator member have mating spherical surfaces.

3. A two degree of freedom pneumatic gyro as set forth in claim1,wherein said air bearing means includes two latitude bands of supportholds on the stator member.

4. 'A two degree of freedom pneumatic gyro including: a rotor member; astator member; air bearing means supporting said rotor member forrotation relative to said stator member; and pneumatic pickoff controlmeans disposed relative to said rotor and stator members and connectedto fluid amplifier means for control thereof, said pickoff control meansincluding four control positions located 90 apart around the peripheryof the stator member, and the rotor member having an innercircumferentially tapered ramp surface and exhaust slots extendingradially from said ramp surface.

5. A two degree of freedom pneumatic gyro as set forth in claim 1,wherein said air bearing means and said pneumatic pickoff control meansare supplied pneumatic control fluid from different sources.

6. A two degree of freedom pneumatic gyro including: a rotor member; astator member; air bearing means supporting said rotor member forrotation relative to said stator member; and pneumatic pickotf controlmeans disposed relative to said rotor and stator members and connectedto fluid amplifier means for control thereof, said rotor and statormembers having mating spherical surfaces, said air bearing meansincluding two latitude bands 4: of support holds on the stator member,said pickolf control means including four control positions locatedapart around the periphery of the stator member, and the rotor memberhaving an inner circumferentially tapered ramp surface and exhaust slotsfor exhausting fluid away from said ramp surface.

7. A two degree of freedom pneumatic gyro as set forth in claim 6,wherein said stator member is mounted in a casing that surrounds therotor and stator members, and said casing having an exhaust openingtherethrough.

8. A pneumatically operated gyro including: a stator member; a rotormember rotatably mounted relative to said stator member, saidrotor andstator members hav- 1 ing mating spherical surfaces; air bearing meanssupporting said rotor member relative to said stator member, said airbearing means including latitude bands of support holds on said statormember; pneumatic means for driving said rotor member relative to saidstator member; and pneumatic pickoff means mounted relative to saidmating spherical surfaces of said rotor and stator members and connectedto at least one fluid amplifier for control thereof to thereby adaptsaid amplifier for actuating control means in one degree of freedom,said pneumatic pickoff means including two control positions locatedapart around theperiphery of the stator member and an innercircumferentially tapered ramp surface-on the rotor member and directlyin front of said control positions.

References Cited by the Examiner UNITED STATES PATENTS 2,852,942 9/1958Gerard 74-5.6 3,139,758 7/1964 Lahde' 74-.-5.6 3,165,282 1/1965 Noyes745.6 X 3,254,538 6/1966 Thomson 745.7

FRED-C. MATTERN JR., Primary Examiner. J. D. PUFFER, Assistant Examiner.

1. A TWO DEGREE OF FREEDOM PNEUMATIC GYRO INCLUDING: A ROTOR MEMBER; ASTATOR MEMBER; AIR BEARING MEANS BETWEEN MATING SURFACES OF SAID ROTORAND STATOR MEMBERS AND SUPPORTING SAID ROTOR MEMBER FOR ROTATIONRELATIVE TO SAID STATOR MEMBER; AND PNEUMATIC PICKOFF CONTROL MEANSDISPOSED RELATIVE TO SAID ROTOR AND STATOR MEMBERS AND CONNECTED TOFLUID AMPLIFIER MEANS FOR CONTROL THEREOF, SAID PNEUMATIC PICKOFFCONTROL MEANS INCLUDING MEANS IN SAID STATOR MEMBER MATING SURFACE ANDCOACTING WITH MEANS ON SAID ROTOR MEMBER MATING SURFACE TO ESTABLISHFLOW RATES TO SAID FLUID AMPLIFIER MEANS THAT ARE PROPORTIONAL TO THEMOVEMENT OF SAID ROTOR MEMBER FROM A PREDETERMINED POSITION, AND MEANSIN SAID ROTOR MEMBER FOR EXHAUSTING FLUID FROM SAID MEANS ON SAID STATORMEMBER MATING SURFACE.